Self-radiated loopback test procedure for millimeter wave antennas

ABSTRACT

Methods and systems for automated testing of extremely-high frequency devices are disclosed. A device under test (DUT) is set in a simultaneous transmit and receive mode. The DUT receives a lower frequency radio frequency (RF) signal from a test unit and up-converts the lower frequency RF signal to a higher frequency RF signal. The DUT transmits the higher frequency RF signal using a first antenna, and receives the higher frequency RF signal using a second antenna. The DUT down-converts the received higher frequency RF signal to a received test RF signal and provides the received test RF signal to the test unit for comparing measurements derived from the received test signal to a design specification for the DUT.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application for patent claims the benefit of U.S.Provisional Application No. 62/751,525, entitled “SELF-RADIATED LOOPBACKTEST PROCEDURE FOR MILLIMETER WAVE ANTENNAS,” filed Oct. 26, 2018,assigned to the assignee hereof, and expressly incorporated herein byreference in its entirety.

TECHNICAL FIELD

Various aspects described herein generally relate to wirelesscommunication systems, and more particularly, to testing of deviceshaving or using millimeter wave (mmW) antennas.

BACKGROUND

Wireless communication systems have developed through variousgenerations, including a first-generation analog wireless phone service(1G), a second-generation (2G) digital wireless phone service (includinginterim 2.5G and 2.75G networks), a third-generation (3G) high speeddata, Internet-capable wireless service and a fourth-generation (4G)service (e.g., Long Term Evolution (LTE) or WiMax). There are presentlymany different types of wireless communication systems in use, includingCellular and Personal Communications Service (PCS) systems. Examples ofknown cellular systems include the cellular Analog Advanced Mobile PhoneSystem (AMPS), and digital cellular systems based on code divisionmultiple access (CDMA), frequency division multiple access (FDMA), timedivision multiple access (TDMA), the Global System for Mobile access(GSM) variation of TDMA, etc.

A fifth generation (5G) mobile standard, referred to as New Radio (NR),calls for higher data transfer speeds, greater numbers of connections,and better coverage, among other improvements. The 5G standard,according to the Next Generation Mobile Networks Alliance, is designedto provide data rates of several tens of megabits per second to each oftens of thousands of users, with 1 gigabit per second to tens of workerson an office floor. Several hundreds of thousands of simultaneousconnections should be supported in order to support large sensordeployments. Consequently, the spectral efficiency of 5G mobilecommunications should be significantly enhanced compared to the current4G standard. Furthermore, signaling efficiencies should be enhanced andlatency should be substantially reduced compared to current standards.

Some wireless communication networks, such as 5G, support operation atvery high and even extremely-high frequency (EHF) bands, such asmillimeter wave (mmW) frequency bands (generally, wavelengths of 1 mm to10 mm, or 10 to 300 GHz). These extremely-high frequencies may supportvery high throughput such as up to six gigabits per second (Gbps). Oneof the challenges for wireless communication at very high orextremely-high frequencies, however, is that a significant propagationloss may occur due to the high frequency. As the frequency increases,the wavelength may decrease, and the propagation loss may increase aswell. At mmW frequency bands, the propagation loss may be severe. Forexample, the propagation loss may be on the order of 22 to 27 dB,relative to that observed in either the 2.4 GHz, or 5 GHz bands.

Transmitting at these extremely-high frequencies places high demands onthe antenna designs and also on testing these devices to ensure that thetransmission and receiving circuitry is operating correctly. Thecharacterization and high volume manufacturing for mmW patch and dipoleantenna modules is extremely challenging. Test solutions are often bulkyas well as expensive due complex equipment and setup traditionallyneeded for testing, such as anechoic chambers for antenna testing.Common challenges include module calibration and multi-site productionon expensive automatic testing equipment (ATE) to support mmWfrequencies. Drawbacks of conventional testing systems include longertest times and large physical size of test systems, thereby requiringlarge floor areas in production environments. It is therefore desired tohave a viable and cost effective solution for testing mmW devices inhigh volumes.

SUMMARY

Various aspects disclosed herein are directed to methods and devices fortesting of devices having or using millimeter wave (mmW) orextremely-high frequency antennas. The following presents a simplifiedsummary relating to one or more aspects disclosed herein. As such, thefollowing summary should not be considered an extensive overviewrelating to all contemplated aspects, nor should the following summarybe regarded to identify key or critical elements relating to allcontemplated aspects or to delineate the scope associated with anyparticular aspect. Accordingly, the following summary has the solepurpose to present certain concepts relating to one or more aspectsrelating to the mechanisms disclosed herein in a simplified form toprecede the detailed description presented below

In an aspect, a method of testing a device under test (DUT) performed bythe DUT includes setting the DUT in a simultaneous transmit and receivemode; receiving a lower frequency radio frequency (RF) signal from atest unit; up-converting the lower frequency RF signal to a higherfrequency RF signal; transmitting the higher frequency RF signal using afirst antenna of the DUT; receiving the higher frequency RF signal usinga second antenna of the DUT; down-converting the received higherfrequency RF signal to a received test RF signal; and providing thereceived test RF signal to the test unit.

In an aspect, a method of testing a DUT performed by a test unitincludes configuring the DUT to set a simultaneous transmit and receivemode; generating a lower frequency RF signal, the test unit comprisingonly lower frequency RF components; providing the lower frequency RFsignal to the DUT; receiving a received test RF signal from the DUT; andcomparing measurements derived from the received test RF signal to adesign specification for the DUT.

In an aspect, a DUT includes a memory; at least one processor coupled tothe memory; and a plurality of antennas coupled to the at least oneprocessor, wherein the at least one processor is configured to set theDUT in a simultaneous transmit and receive mode; wherein at least one ofthe plurality of antennas is configured to receive a lower frequency RFsignal from a test unit; wherein the at least one processor isconfigured to up-convert the lower frequency RF signal to a higherfrequency RF signal; wherein a first antenna of the plurality ofantennas is configured to transmit the higher frequency RF signal;wherein a second antenna of the plurality of antennas is configured toreceive the higher frequency RF signal using a second antenna of theDUT; wherein the at least one processor is configured to down-convertthe received higher frequency RF signal to a received test RF signal;and wherein the at least one processor is configured to provide thereceived test RF signal to the test unit.

In an aspect, a device test system, including a test unit, includes asignal generator configured to generate a lower frequency RF signal andto provide the lower frequency RF signal to a DUT, the test unitcomprising only lower frequency RF components; a signal analyzerconfigured to receive a received test RF signal from the DUT and tocompare measurements from the received test RF signal to a designspecification for the DUT; and a fixture for mounting the DUT to thetest unit.

In an aspect, an apparatus for testing a DUT includes means of the DUTfor setting the DUT in a simultaneous transmit and receive mode; meansof the DUT for receiving a lower frequency RF signal from a test unit;means of the DUT for up-converting the lower frequency RF signal to ahigher frequency RF signal; means of the DUT for transmitting the higherfrequency RF signal using a first antenna of the DUT; means of the DUTfor receiving the higher frequency RF signal using a second antenna ofthe DUT; means of the DUT for down-converting the received higherfrequency RF signal to a received test RF signal; and means of the DUTfor providing the received test RF signal to the test unit.

In an aspect, an apparatus for testing a DUT includes means of a testunit for configuring the DUT to set a simultaneous transmit and receivemode; means of the test unit for generating a lower frequency RF signal,the test unit comprising only lower frequency RF components; means ofthe test unit for providing the lower frequency RF signal to the DUT;means of the test unit for receiving a received test RF signal from theDUT; and means of the test unit for comparing measurements derived fromthe received test RF signal to a design specification for the DUT.

In an aspect, a non-transitory computer-readable medium storingcomputer-executable instructions includes computer-executableinstructions comprising at least one instruction instructing a DUT toset the DUT in a simultaneous transmit and receive mode; at least oneinstruction instructing the DUT to receive a lower frequency RF signalfrom a test unit; at least one instruction instructing the DUT toup-convert the lower frequency RF signal to a higher frequency RFsignal; at least one instruction instructing the DUT to transmit thehigher frequency RF signal using a first antenna of the DUT; at leastone instruction instructing the DUT to receive the higher frequency RFsignal using a second antenna of the DUT; at least one instructioninstructing the DUT to down-convert the received higher frequency RFsignal to a received test RF signal; and at least one instructioninstructing the DUT to provide the received test RF signal to the testunit.

In an aspect, a non-transitory computer-readable medium storingcomputer-executable instructions includes computer-executableinstructions comprising at least one instruction instructing a test unitto configure the DUT to set a simultaneous transmit and receive mode; atleast one instruction instructing the test unit to generate a lowerfrequency RF signal, the test unit comprising only lower frequency RFcomponents; at least one instruction instructing the test unit toprovide the lower frequency RF signal to the DUT; at least oneinstruction instructing the test unit to receive a received test RFsignal from the DUT; and at least one instruction instructing the testunit to compare measurements derived from the received test RF signal toa design specification for the DUT.

Other objects and advantages associated with the aspects disclosedherein will be apparent to those skilled in the art based on theaccompanying drawings and detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the various aspects described herein andmany attendant advantages thereof will be readily obtained as the samebecomes better understood by reference to the following detaileddescription when considered in connection with the accompanying drawingswhich are presented solely for illustration and not limitation, and inwhich:

FIG. 1 illustrates an exemplary process of testing devices having orusing mmW or EHF antennas according to various aspects of thedisclosure.

FIG. 2 illustrates further aspects of the exemplary process of testingdevices having or using mmW or EHF antennas according to various aspectsof the disclosure.

FIG. 3 illustrates further aspects of the exemplary testing processperformed at a test unit according to various aspects of the disclosure.

FIG. 4. illustrates an exemplary testing system according to variousaspects of the disclosure.

FIG. 5A illustrates a plurality of antennas of a module that can be usedas a DUT according to various aspects of the disclosure.

FIG. 5B illustrates the pairing of various antennas according to variousaspects of the disclosure.

FIG. 5C illustrates various design options for antenna modules accordingto various aspects of the disclosure.

FIG. 5D illustrates a user equipment (UE) and an antenna module that canbe used as DUTs according to various aspects of the disclosure.

FIG. 6 illustrates a module that can be used as a DUT according tovarious aspects of the disclosure.

FIG. 7 illustrates another module that can be used as a DUT according tovarious aspects of the disclosure.

FIG. 8 illustrates an exemplary wireless communications system accordingto various aspects of the disclosure.

FIG. 9 illustrates an exemplary base station and exemplary UE in anaccess network according to various aspects of the disclosure.

DETAILED DESCRIPTION

Various aspects described herein generally relate to testing of deviceshaving mmW and/or EHF antennas. Some ATE systems are focused on testingmultiple antenna devices or modules including patch and dipole antennas.Included in the various aspects disclosed herein are self-radiatedloopback methods and devices that can use patch and dipole antennas onthe DUT (or coupled to the DUT for testing purposes) for performingtransmit and receive tests. For example, the self-radiated loopbackmethods and devices allow for transmissions from one patch or dipoleantenna to be measured on another of the patch or dipole antennas vianear-field coupling. The self-radiated loopback test methods and devices(e.g., test units) can be used for mmW frequencies. According to thevarious aspects disclosed, the DUT is self-contained for mmWmeasurements and no external mmW equipment is used for the measurements.The various aspects disclosed herein allow for very low cost testsolutions, which dramatically improves the area under the curve (AUC) ofthe modules being tested/DUTs. Additionally, the various aspectsdisclosed herein allow for a robust and reliable test platform that canimprove time to market for the tested modules and devices that use thesemodules. Further, the various aspects disclosed herein allow forcalibration and testing of the modules (e.g., phaser/antenna modules)inside end devices (e.g., UEs, mobile phones, etc.).

For example, for lower frequency components (e.g., antennas configuredfor sub-20 GHz operation), the substrates to which the antennas areattached can be a printed circuit board (PCB). However, for mmW-capableantennas, substrates with lower loss at mmW frequencies should be used.In addition, the cables, connectors, etc. used for mmW testing aretypically much larger in size and/or more expensive than the cables,connectors, etc. used for lower frequency testing. Further, thesocket/interface can be cheaper for lower frequency testing than for mmWtesting. Additionally, mmW parasitics are much higher, and thus, thetest equipment has to mitigate for such parasitics, which adds to thecost of the components.

These and other aspects are disclosed in the following description andrelated drawings to show specific examples relating to exemplaryaspects. Alternate aspects will be apparent to those skilled in thepertinent art upon reading this disclosure, and may be constructed andpracticed without departing from the scope or spirit of the disclosure.Additionally, well-known elements will not be described in detail or maybe omitted so as to not obscure the relevant details of the aspectsdisclosed herein.

The word “exemplary” is used herein to mean “serving as an example,instance, or illustration.” Any aspect described herein as “exemplary”is not necessarily to be construed as preferred or advantageous overother aspects. Likewise, the term “aspects” does not require that allaspects include the discussed feature, advantage, or mode of operation.

The terminology used herein describes particular aspects only and shouldnot be construed to limit any aspects disclosed herein. As used herein,the singular forms “a,” “an,” and “the” are intended to include theplural forms as well, unless the context clearly indicates otherwise.Those skilled in the art will further understand that the terms“comprises,” “comprising,” “includes,” and/or “including,” as usedherein, specify the presence of stated features, integers, steps,operations, elements, and/or components, but do not preclude thepresence or addition of one or more other features, integers, steps,operations, elements, components, and/or groups thereof.

Further, various aspects may be described in terms of sequences ofactions to be performed by, for example, elements of a computing device.Those skilled in the art will recognize that various actions describedherein can be performed by specific circuits (e.g., an applicationspecific integrated circuit (ASIC)), by program instructions beingexecuted by one or more processors, or by a combination of both.Additionally, these sequences of actions described herein can beconsidered to be embodied entirely within any form of non-transitorycomputer-readable medium having stored thereon a corresponding set ofcomputer instructions that upon execution would cause an associatedprocessor to perform the functionality described herein. Thus, thevarious aspects described herein may be embodied in a number ofdifferent forms, all of which have been contemplated to be within thescope of the claimed subject matter. In addition, for each of theaspects described herein, the corresponding form of any such aspects maybe described herein as, for example, “logic configured to” and/or otherstructural components configured to perform the described action.

As used herein, the terms “user equipment” (or “UE”), “user device,”“user terminal,” “client device,” “communication device,” “wirelessdevice,” “wireless communications device,” “handheld device,” “mobiledevice,” “mobile terminal,” “mobile station,” “handset,” “accessterminal,” “subscriber device,” “subscriber terminal,” “subscriberstation,” “terminal,” and variants thereof may interchangeably refer toany suitable mobile or stationary device that can receive wirelesscommunication and/or navigation signals. These terms are also intendedto include devices which communicate with another device that canreceive wireless communication and/or navigation signals such as byshort-range wireless, infrared, wireline connection, or otherconnection, regardless of whether satellite signal reception, assistancedata reception, and/or position-related processing occurs at the deviceor at the other device. In addition, these terms are intended to includeall devices, including wireless and wireline communication devices thatcan communicate with a core network via a radio access network (RAN) andthrough the core network the UEs can be connected with external networkssuch as the Internet and with other UEs. Of course, other mechanisms ofconnecting to the core network and/or the Internet are also possible forthe UEs, such as over a wired access network, a wireless local areanetwork (WLAN) (e.g., based on IEEE 802.11, etc.) and so on. UEs can beembodied by any of a number of types of devices including but notlimited to printed circuit (PC) cards, compact flash devices, externalor internal modems, wireless or wireline phones, smartphones, tablets,tracking devices, asset tags, and so on.

As noted above, the various aspects described herein generally relate totesting of devices or modules that include mmW and/or EHF antennas.These antennas can be used in devices used in high data ratecommunication systems, such as 4G and 5G wireless communication systems,and in particular, can be used in wireless communication systems withbeam forming and multi-beam transmission and reception.

FIG. 1 illustrates an exemplary process 100 of testing devices having orusing mmW or EHF antennas. The process 100 begins with the DUT being setin a simultaneous transmit and receive mode, at 102. At 104, a lowerfrequency RF signal can be received from a test unit. The test signalcan be generated by a signal generator in the test unit. Further, thetest signal test can be an intermediate frequency (IF) signal (i.e.,sub-mmW) for testing the antennas. At 106, the DUT can up-convert thelower frequency RF signal to a higher frequency RF signal. At 108, theDUT can transmit the higher frequency RF signal over the air using afirst antenna of the DUT.

It is understood that RF signals (e.g., the lower and higher frequencyRF signals described above) can cover a broad range of frequencies (aswill be described further below) and, as such, in the context of a mmWradiated signal, an IF signal could also have a frequency considered tobe an RF signal. In an aspect, the lower frequency RF signal may be acontinuous wave RF signal, or a modulated and/or a multi-tone lowerfrequency test signal. For example, the IF signal (i.e., the lowerfrequency RF signal) could have a frequency within the single-digit GHzrange, for example, 8-9 GHz. In such an implementation, in one example,the antenna module of the DUT could be configured to up-convert the 8-9GHz IF signal to, for example, a 38-39 GHz mmW signal (i.e., the higherfrequency RF signal) by mixing the IF signal with, for example, a 30 GHzmmW local oscillator.

At 110, the higher frequency RF signal is received at the DUT using asecond antenna. At 112, the higher frequency RF signal received at thesecond antenna can be down-converted, and at 114, the down-convertedtest signal can be provided to the test unit for evaluation andcomparison to design specifications for the DUT.

It will be appreciated that according to the various aspects disclosed,many other additions and/or modifications can be made to the process 100discussed above. For example, the DUT can transmit on a first layer(e.g., multiple-input and multiple-output (MIMO) layer 1) and receive ona second layer (e.g., MIMO layer 2). In some aspects, the first antennaand the second antenna can be selected from a plurality of antennas, ifthe DUT includes more than two antennas. The plurality of antennas maybe integrated into the DUT. The plurality of antennas can be formed on acommon substrate within the DUT, or may be formed on two or moresubstrates of the DUT.

Alternatively, the plurality of antennas may be coupled to the DUT priorto testing. For example, an antenna module with a plurality of antennasmay be attached to a DUT without integrated antennas, prior toperforming the self-radiated loopback test methods disclosed herein.

If there are more than two antennas in the DUT, the first antenna andthe second antenna may be separated by at least one other antenna of theplurality of antennas. Additionally, each of the plurality of antennasmay include both a dipole antenna and a patch antenna. In that case, insome aspects, the dipole antennas may be independently tested togetherand likewise the patch antennas may be independently tested together. Insome implementations, the patch antennas and dipole antennas can beconsidered independent antennas.

Regardless of the number antennas in the DUT, the transmitting (block108) and receiving (block 110) may be performed by a single transceiverintegrated circuit (IC) that is part of the DUT and coupled to theplurality of antennas. Further, it will be appreciate that the DUT mayinclude other ICs and active and/or passive devices. For example, insome aspects, the DUT may include a power management IC. Accordingly,the discussion and representation of the DUT configurations providedherein are merely illustrative and are not an exhaustive detailing ofthe various DUT configurations contemplated to be within the scope ofthe disclosure.

FIG. 2 illustrates further aspects of the exemplary process of testingdevices having or using mmW or EHF antennas. As illustrated, the processcan continue to check the transmit and receive functioning of eachantenna. At 202, a second lower frequency RF signal is received from thetest unit, which can be the same as the original signal discussed above.At 204, the DUT can up-convert the second lower frequency RF signal to asecond higher frequency RF signal. At 206, the second higher frequencyRF signal is transmitted from the DUT using the second antenna(previously used to receive). At 208, the second higher frequency RFsignal is received at the DUT using the first antenna (previously usedto transmit). At 210, the second higher frequency RF signal received atthe first antenna can be down-converted to a second received test RFsignal. At 212, the second received test RF signal can be provided tothe test unit for evaluation and comparison to design specifications forthe DUT. Accordingly, both antennas will have been tested for bothtransmitting and receiving. Optionally, at 214, the testing process canbe repeated for additional antennas in the DUT, so all antennas in theDUT can be tested and characterized. Further, it will be appreciatedthat according to the various aspects disclosed that the additionsand/or modifications discussed in relation to FIG. 1 may also apply tothe process discussed in relation to FIG. 2.

FIG. 3 illustrates an exemplary testing process 300 performed at thetest unit. At 302, the test unit configures the DUT to set asimultaneous transmit and receive mode. At 304, a lower frequency RFsignal is generated at the test unit. At 306, the lower frequency RFsignal is provide to the DUT. After the DUT performs operations 104 to110 of FIG. 1, at 308, a received test RF signal is received from theDUT. At 310, measurements derived from the received test RF signal arecompared to a design specification for the DUT. Comparing themeasurements can include the test unit calculating and comparingreceiver gain and transmit power at the DUT to the design specification.As discussed above, the test signal can be an IF signal, which can begenerated by a signal generator in the test unit. It will be appreciatedthat the self-radiated loopback testing process 300, from the test unitperspective, has related aspects to the processes discussed above withreference to FIGS. 1 and 2, so a detailed explanation of similar aspectswill not be provided.

FIG. 4 illustrates an exemplary testing system according to variousaspects of the disclosure. In one example, a test system can include atest unit 400. The test unit 400 includes a signal generator 402configured to generate a test signal (e.g., a lower frequency RF signal)and provide the test signal to a DUT 410, as described above withreference to, for example, blocks 304 and 306 of FIG. 3. In an aspect,the test unit 400 may include only lower frequency RF signal components,for example, RF signal components that that are only capable ofprocessing frequencies less than 20 GHz.

The test unit 400 also includes a signal analyzer 402 configured toreceive a signal that is a down-converted version of the test signalreceived from the DUT 410 and to compare measurements from the receivedsignal to a design specification for the DUT 410, as described abovewith reference to, for example, block 308 and 310 of FIG. 3. A fixture404 is also provided for mounting the DUT 410 to the test unit 400. Itwill be appreciated that the various functions of the test unit 400attributed to elements listed above (e.g., signal generator and signalanalyzer) may be performed by one or more processors in one device ormultiple devices operably configured with appropriate code and coupledto various input and output devices (e.g., analog and/or digital inputsand outputs) to perform the various functions disclosed herein.Accordingly, it will be appreciated that the various aspects describeherein are not limited to the example illustrations.

The signal generator may be a vector signal generator (VSG). The signalanalyzer may be a vector signal analysis/analyzer (VSA). In theillustration, the signal generator and signal analyzer are show as acommon signal generator/analyzer device 402, as these functionalitiesmay be integrated into a common device or may be separate devices, as isknown in the art.

The IF signal generated by the signal generator/analyzer device 402 isup-converted at the DUT 410 to an RF signal, for example a mmW signal,and is transmitted 412 from the DUT 410, as discussed above withreference to blocks 106 and 108 of FIG. 1. Additionally, as discussedabove with reference to blocks 110 to 114, the looped back RF signal,for example a mmW signal, is received 414 at the DUT 410 and isdown-converted, and that down-converted received signal is provide tothe signal generator/analyzer device 402.

As is known in the art, the signal generator can generate test signalsincluding complex modulated signals related to various wirelessstandards, which are included in the modulated IF signal. The signalanalyzer receives the complex modulated received signal as an input tothe VSA. This received signal is digitized to obtain baseband signals.Various mathematical equations can be applied on this baseband signal tomeasure and plot various parameters. The test unit can derivemeasurements and parameters information, such as receiver gain, transmitpower, error vector magnitude (EVM), adjacent channel leakage powerratio (ACLR), intermodulation distortion, and/or additional signalparameters that can be used to verify the DUT's 410 performance relativeto the design specification for the DUT 410. These measurements, whencompared to the design specification for the DUT 410, can be used todetermine whether the DUT 410 is functioning properly. Additionally,errors, such as disabled/defective transmit and receive circuits, can bedetected. The DUT 410 can be connected to the fixture 404 of the testunit 400 to aid in quick installation and testing of various DUTs. Thefixture 404 can also include a socket for easy coupling of the DUT 410connections to the test unit 400 for testing.

Additionally, as described above, in the test system, the DUT 410 isconfigured to operate in a simultaneous transmit and receive mode, toreceive the test signal from the test unit 400, to transmit the testsignal from the DUT 410 using a first antenna, to receive the testsignal at the DUT 410 using a second antenna, and to provide thereceived test signal to the test unit 400. Additional testing aspectsand functionalities of the DUT 410 and test unit 400, where discussed inthe foregoing description of the various processes, will not be repeatedherein for brevity.

FIG. 5A illustrates a plurality of antennas of a module that can be usedas a DUT according to aspects of the disclosure. As illustrated, antenna501, antenna 502, antenna 503, and antenna 504 are each formed on acommon substrate. Antenna 501 includes both a dipole antenna 511 and apatch antenna 521. Antenna 502 includes both a dipole antenna 512 and apatch antenna 522. Antenna 503 includes both a dipole antenna 513 and apatch antenna 523. Antenna 504 includes both a dipole antenna 514 and apatch antenna 524. Each antenna as illustrated contains both a dipoleand patch antenna, however, the various aspects disclosed are notlimited to this configuration, as an antenna may have only one dipoleantenna, one patch antenna, multiple dipole antennas, multiple patchantennas, or any combination thereof. Additionally or alternatively, thepatch and dipole antennas can be considered each as independent antennasof the plurality of antennas of the module. In the illustrated example,antenna 502 is transmitting an RF signal illustrated as broad beam 505.Power from one patch antenna (521, 522, 523, or 524) or dipole antenna(e.g., 511, 512, 513, or 514) can be measure on nearby patches/dipoles.While some implementations may generally transmit from one patch antennaand receive on another patch antenna, or transmit from one dipoleantenna and receive on another dipole antenna, it is understood that inother implementations, the test signal may be transmitted using one ofthe patch or dipole antenna while the test signal is received by theother of the patch or dipole antenna.

In one example, a patch antenna can support multiple mmW frequencies fortransmission and reception, for example, a patch antenna could beconfigured to support both 28 GHz and 39 GHz measurements. Both 28 GHzand 39 GHz measurements at horizontal (H) and vertical (V) polarizationscould, in such an example, be performed using antennas of the DUTitself. No external mmW equipment at the test unit is required for thetest measurements. The thicker arrows represent that nearby patchantennas will receive more power than the far patch antennas. Althougheach of the adjacent antennas receives RF power from the transmission,antenna 504 is selected to receive the RF signal in this illustratedexample. As discussed herein, according to one aspect, the transmittingantenna and receiving antenna of the antenna array can be separated byat least one antenna. In another example, the antenna of the antennaarray transmitting a test signal and the antenna of the antenna arrayreceiving the test signal are spaced apart a distance greater than thesmallest distance between any two antennas in the array.

FIG. 5B illustrates the pairing of various antennas according to thevarious aspects disclosed. As noted above, power from one patch antenna(e.g., 521, 522, 523, or 524) or dipole antenna (e.g., 511, 512, 513, or514) can be measured on nearby antennas during testing. In one example,the patch antennas 521 and 523 can be paired for testing as can patchantennas 522 and 524 be paired for testing. Likewise, dipole antennas511 and 513 can be paired for testing as can dipole antennas 512 and 514be paired for testing. Since the antenna pairs will be used in both thereceive and transmit mode, all the patch and dipole antennas can betested. In the illustrated example, each antenna pair can be testedindividually, for example, a first patch antenna transmits and a secondpatch antenna to which it is paired for testing receives thetransmission. The functions can thereafter be reversed and the secondpatch antenna transmits and the first patch antenna receives thetransmission. However, the various aspects disclosed herein are notlimited to these specific illustrations. Accordingly, variouscombinations of antennas may be used for testing based on the moduledesign being tested and test parameter considerations.

As illustrated in FIG. 5B, patch antennas and/or dipole antennas may beconnected to different MIMO layers when useful to allow for simultaneoustransmission and reception, for example, in implementations wheretransmission and reception in a single layer share a common line, forexample, an IF line. For example, patch antenna 521 is connected totraces H1 and V1, patch antenna 522 is connected to traces H2 and V2,patch antenna 523 is connected to traces H3 and V3, patch antenna 524 isconnected to traces H4 and V4, dipole antenna 511 is connected to tracesD1 and D2, dipole antenna 512 is connected to traces D3 and D4, dipoleantenna 513 is connected to traces D5 and D6, and dipole antenna 514 isconnected to traces D7 and D8. In the illustrated implementation, someof traces H1, H2, H3, H4, V1, V2, V3, and V4 are formed on one MIMOlayer, for example a first MIMO layer (e.g., MIMO layer 1), while othersof H1, H2, H3, H4, V1, V2, V3, and V4 are formed on another MIMO layer,for example a second MIMO layer (e.g., MIMO layer 2).

Also, in the illustrated example, each dipole antenna is illustrated asconnected to two traces. For each dipole antenna, both traces are formedin the same MIMO layer, as the dipole antennas have differential inputsand/or outputs. Hence, in one such example, two of the dipole antennasillustrated each have two traces formed in one of the first or secondMIMO layers and another two of the dipole antennas illustrated each havetraces formed in another of the first or second MIMO layers. Hence, inimplementations where the DUT transmits using a first MIMO layer andreceives using a second MIMO layer, and where there are relatively fewMIMO layers, for example two layers, transmit antenna and receiveantenna pairs may be limited only to antenna pair combinations where oneantenna can be driven using one of the two MIMO layers and the otherantenna can receive using the other of the two MIMO layers. However, inalternative implementations, other hardware features can be used toenable the capability to transmit with one antenna while receiving withanother antenna of the plurality of antennas.

FIG. 5C illustrates various design options for antenna modules accordingto various aspects disclosed herein. As illustrated, in oneconfiguration, an antenna module 530 can include a plurality of patchantennas. Each of the plurality of patch antennas can have two patchantennas tuned for two different frequencies (e.g., 28 GHz and 39 GHz).Each of the patch antennas may have horizontal (H) and vertical (V)polarizations. In the configuration of antenna module 530, the patchantennas tuned for the two different frequencies are overlapping. In theconfiguration of antenna module 540, the patch antennas tuned for thetwo different frequencies are adjacent. As noted above, it will beappreciated that the various aspects disclosed herein are not limited tothese specific illustrations. Accordingly, various combinations ofantenna configurations may be used based on the module design beingtested, frequencies being used, and other test parameter considerations.

FIG. 5D illustrates a UE 500 and associated antenna modules 550 that canbe used as a DUT according to aspects of the disclosure. As illustrated,the UE 500 may contain multiple antenna modules 550 to provide forbetter spherical coverage of the transmitted beam(s) and receivedbeam(s). Each antenna module 550 can contain a linear array of patch anddipole antennas as illustrated and discussed in the foregoingdisclosure. The patch antennas may provide dual polarization, forexample, in the y-z plane as illustrated by beam pattern 552. The dipoleantenna may have a single polarization and provide a narrow beam in thex-z or x-y planes, as illustrated by beam pattern 554. Various moduleconfigurations and UE details will be provide in the followingparagraphs.

Tailoring or optimizing the RF waveform for the low frequency test RFsignal can be useful to enable testing of various aspects of the RFand/or mmW modules in the DUT, including, for example, the non-linearitytransmit and receive performance, EVM, intermodulation distortion,receive linearity, power amplifier (PA) linearity, transmit signal pathgain and linearity, mixer performance/design, port-to-port variation,antenna gain, antenna isolation, antenna coupling, and impedancemismatch between various components (such as testing for an impedancemismatch between the PA and antenna). The test unit should set the DUTinto different gain modes to fine tune the transmit gain mode and thereceive gain mode, and fine tune the antenna combinations.

FIG. 6 illustrates a module 600 that can be used as a DUT according toexemplary aspects of the disclosure. The DUT can be a module 600 thatincludes a transceiver IC 602, a power management IC 604 that regulatesand supplies power to the various components on the module, and aconnector 606 that can be used to couple to another module and/or to atest fixture. In this configuration, the module 600 also includes testpoints 608. Further, the module 600 includes a plurality of antennas610, illustrated as four dipole antennas 610, which may also includeassociated patch antennas not viewable from the illustrated side of themodule 600. It will be appreciated that additional components (e.g.,various passive and/or active surface-mount devices (SMDs)) may beprovided on the illustrated module 600. Likewise, certain designfeatures are illustrated in FIG. 6 related to the module 600. However,these additional features are merely associated with the specificillustration of the module 600, which is used to represent an example ofthe DUT components discussed in the foregoing disclosure. Accordingly,the various aspects disclosed herein are not limited to this illustratedexample.

FIG. 7 illustrates another module 700 that can be used as a DUTaccording to exemplary aspects of the disclosure. The DUT can be amodule 700 that includes a transceiver IC 702, a power management IC 704that regulates and supplies power to the various components on themodule, and a connector 706 that can be used to couple to another moduleand/or to a test fixture. Additionally, the module 700 includes aplurality of antennas 710, illustrated as four dipole antennas 710,which may also include associated patch antennas not viewable from theillustrated side of the module 700. It will be appreciated thatadditional components (e.g., various passive and/or active SMDs) may beprovided on the illustrated module 700. Likewise, certain designfeatures are illustrated in FIG. 7 related to the module 700. However,these additional features are merely associated with the specificillustration of the module 700, which is used to represent an example ofthe DUT components discussed in the foregoing disclosure. Accordingly,the various aspects disclosed herein are not limited to this illustratedexample.

As noted above, the various aspects described herein generally relate totesting of devices or modules that are part of devices that include mmWand/or EHF antennas. These antennas can be used in UEs and other devicesused in high data rate communication systems, including 4G and 5Gwireless communication systems, and in particular, can be used inwireless communication systems with beam forming and multi-beamtransmission and reception. Examples of the UEs and wirelesscommunication systems that utilize these devices are provided in thefollowing paragraphs.

According to various aspects, FIG. 8 illustrates an exemplary wirelesscommunications system 800. The wireless communications system 800 (whichmay also be referred to as a wireless wide area network (WWAN)) mayinclude various base stations 802 and various UEs 804. The base stations802 may include macro cell base stations (high power cellular basestations) and/or small cell base stations (low power cellular basestations). In an aspect, the macro cell base station may include evolvedNodeBs (eNBs) where the wireless communications system 800 correspondsto an LTE network, or New Radio NodeBs (gNBs) where the wirelesscommunications system 800 corresponds to a NR network, or a combinationof both, and the small cell base stations may include femtocells,picocells, microcells, etc.

The base stations 802 may collectively form a radio access network (RAN)and interface with a core network 870 (e.g., an evolved packet core(EPC) or next generation core (NGC)) through backhaul links 822, andthrough the core network 870 to one or more application servers 872. Inaddition to other functions, the base stations 802 may perform functionsthat relate to one or more of transferring user data, radio channelciphering and deciphering, integrity protection, header compression,mobility control functions (e.g., handover, dual connectivity),inter-cell interference coordination, connection setup and release, loadbalancing, distribution for non-access stratum (NAS) messages, NAS nodeselection, synchronization, RAN sharing, multimedia broadcast multicastservice (MBMS), subscriber and equipment trace, RAN informationmanagement (RIM), paging, positioning, and delivery of warning messages.The base stations 802 may communicate with each other directly orindirectly (e.g., through the EPC/NGC) over backhaul links 834, whichmay be wired or wireless.

The base stations 802 may wirelessly communicate with the UEs 804. Eachof the base stations 802 may provide communication coverage for arespective geographic coverage area 810. In an aspect, one or more cellsmay be supported by a base station 802 in each coverage area 810. A“cell” is a logical communication entity used for communication with abase station (e.g., over some frequency resource, referred to as acarrier frequency, component carrier, carrier, band, or the like), andmay be associated with an identifier (e.g., a physical cell identifier(PCID), a virtual cell identifier (VCID)) for distinguishing cellsoperating via the same or a different carrier frequency. In some cases,different cells may be configured according to different protocol types(e.g., machine-type communication (MTC), narrowband IoT (NB-IoT),enhanced mobile broadband (eMBB), or others) that may provide access fordifferent types of UEs. Because a cell is supported by a specific basestation, the term “cell” may refer to either or both the logicalcommunication entity and the base station that supports it, depending onthe context. In some cases, the term “cell” may also refer to ageographic coverage area of a base station (e.g., a sector), insofar asa carrier frequency can be detected and used for communication withinsome portion of geographic coverage areas 810.

While neighboring macro cell base station 802 geographic coverage areas810 may partially overlap (e.g., in a handover region), some of thegeographic coverage areas 810 may be substantially overlapped by alarger geographic coverage area 810. For example, a small cell basestation 802′ may have a coverage area 810′ that substantially overlapswith the coverage area 810 of one or more macro cell base stations 802.A network that includes both small cell and macro cell base stations maybe known as a heterogeneous network. A heterogeneous network may alsoinclude home eNBs (HeNBs), which may provide service to a restrictedgroup known as a closed subscriber group (CSG).

The communication links 820 between the base stations 802 and the UEs804 may include UL (also referred to as reverse link) transmissions froma UE 804 to a base station 802 and/or downlink (DL) (also referred to asforward link) transmissions from a base station 802 to a UE 804. Thecommunication links 820 may use MIMO antenna technology, includingspatial multiplexing, beamforming, and/or transmit diversity. Thecommunication links 820 may be through one or more carrier frequencies.Allocation of carriers may be asymmetric with respect to DL and UL(e.g., more or less carriers may be allocated for DL than for UL).

The wireless communications system 800 may further include a wirelesslocal area network (WLAN) access point (AP) 850 in communication withWLAN stations (STAs) 852 via communication links 854 in an unlicensedfrequency spectrum (e.g., 5 GHz). When communicating in an unlicensedfrequency spectrum, the WLAN STAs 852 and/or the WLAN AP 850 may performa clear channel assessment (CCA) or listen before talk (LBT) procedureprior to communicating in order to determine whether the channel isavailable.

More specifically, LBT is a mechanism by which a transmitter (e.g., a UEon the uplink or a base station on the downlink) applies CCA beforeusing the channel/subband. Thus, before transmission, the transmitterperforms a CCA check and listens on the channel/subband for the durationof the CCA observation time, which should not be less than somethreshold (e.g., 15 microseconds). The channel may be consideredoccupied if the energy level in the channel exceeds some threshold(proportional to the transmit power of the transmitter). If the channelis occupied, the transmitter should delay further attempts to access themedium by some random factor (e.g., some number between 1 and 20) timesthe CCA observation time. If the channel is not occupied, thetransmitter can begin transmitting. However, the maximum contiguoustransmission time on the channel should be less than some threshold,such as 5 milliseconds.

The small cell base station 802′ may operate in a licensed and/or anunlicensed frequency spectrum. When operating in an unlicensed frequencyspectrum, the small cell base station 802′ may employ LTE or NRtechnology and use the same 5 GHz unlicensed frequency spectrum as usedby the WLAN AP 850. The small cell base station 802′, employing LTE/5Gin an unlicensed frequency spectrum, may boost coverage to and/orincrease capacity of the access network. NR in unlicensed spectrum maybe referred to as NR-U. LTE in an unlicensed spectrum may be referred toas LTE-U, licensed assisted access (LAA), or MulteFire.

The wireless communications system 800 may further include a mmW basestation 880 that may operate in mmW frequencies and/or near mmWfrequencies in communication with a UE 882. Extremely high frequency(EHF) is part of the RF in the electromagnetic spectrum. EHF has a rangeof 30 GHz to 300 GHz and a wavelength between 1 millimeter and 10millimeters. Radio waves in this band may be referred to as a millimeterwave. Near mmW may extend down to a frequency of 3 GHz with a wavelengthof 100 millimeters. The super high frequency (SHF) band extends between3 GHz and 30 GHz, also referred to as centimeter wave. Communicationsusing the mmW/near mmW radio frequency band have high path loss and arelatively short range. The mmW base station 880 and the UE 882 mayutilize beamforming (transmit and/or receive) over a mmW communicationlink 884 to compensate for the extremely high path loss and short range.For example, the beamforming can be achieved using antenna arraysincluding multiple antennas, for example, as described above withreference to the various modules in FIGS. 5A to 7. Further, it will beappreciated that in alternative configurations, one or more basestations 802 may also transmit using mmW or near mmW and beamforming.Accordingly, it will be appreciated that the foregoing illustrations aremerely examples and should not be construed to limit the various aspectsdisclosed herein.

Transmit beamforming is a technique for focusing an RF signal in aspecific direction. Traditionally, when a network node (e.g., a basestation) broadcasts an RF signal, it broadcasts the signal in alldirections (omni-directionally). With transmit beamforming, the networknode determines where a given target device (e.g., a UE) is located(relative to the transmitting network node) and projects a strongerdownlink RF signal in that specific direction, thereby providing afaster (in terms of data rate) and stronger RF signal for the receivingdevice(s). To change the directionality of the RF signal whentransmitting, a network node can control the phase and relativeamplitude of the RF signal at each of the one or more transmitters thatare broadcasting the RF signal. For example, a network node may use anarray of antennas (referred to as a “phased array” or an “antennaarray”) that creates a beam of RF waves that can be “steered” to pointin different directions, without actually moving the antennas.Specifically, the RF current from the transmitter is fed to theindividual antennas with the correct phase relationship so that theradio waves from the separate antennas add together to increase theradiation in a desired direction, while cancelling to suppress radiationin undesired directions.

Transmit beams may be quasi-collocated, meaning that they appear to thereceiver (e.g., a UE) as having the same parameters, regardless ofwhether or not the transmitting antennas of the network node themselvesare physically collocated. In NR, there are four types ofquasi-collocation (QCL) relations. Specifically, a QCL relation of agiven type means that certain parameters about a second reference RFsignal on a second beam can be derived from information about a sourcereference RF signal on a source beam. Thus, if the source reference RFsignal is QCL Type A, the receiver can use the source reference RFsignal to estimate the Doppler shift, Doppler spread, average delay, anddelay spread of a second reference RF signal transmitted on the samechannel. If the source reference RF signal is QCL Type B, the receivercan use the source reference RF signal to estimate the Doppler shift andDoppler spread of a second reference RF signal transmitted on the samechannel. If the source reference RF signal is QCL Type C, the receivercan use the source reference RF signal to estimate the Doppler shift andaverage delay of a second reference RF signal transmitted on the samechannel. If the source reference RF signal is QCL Type D, the receivercan use the source reference RF signal to estimate the spatial receiveparameter of a second reference RF signal transmitted on the samechannel.

In receive beamforming, the receiver uses a receive beam to amplify RFsignals detected on a given channel. For example, the receiver canincrease the gain setting and/or adjust the phase setting of an array ofantennas in a particular direction to amplify (e.g., to increase thegain level of) the RF signals received from that direction. Thus, when areceiver is said to beamform in a certain direction, it means the beamgain in that direction is high relative to the beam gain along otherdirections, or the beam gain in that direction is the highest comparedto the beam gain in that direction of all other receive beams availableto the receiver. This results in a stronger received signal strength(e.g., reference signal received power (RSRP), reference signal receivedquality (RSRQ), signal-to-interference-plus-noise ratio (SINR), etc.) ofthe RF signals received from that direction.

Receive beams may be spatially related. A spatial relation means thatparameters for a transmit beam for a second reference signal can bederived from information about a receive beam for a first referencesignal. For example, a UE may use a particular receive beam to receive areference downlink reference signal (e.g., synchronization signal block(SSB)) from a base station. The UE can then form a transmit beam forsending an uplink reference signal (e.g., sounding reference signal(SRS)) to that base station based on the parameters of the receive beam.

Note that a “downlink” beam may be either a transmit beam or a receivebeam, depending on the entity forming it. For example, if a base stationis forming the downlink beam to transmit a reference signal to a UE, thedownlink beam is a transmit beam. If the UE is forming the downlinkbeam, however, it is a receive beam to receive the downlink referencesignal. Similarly, an “uplink” beam may be either a transmit beam or areceive beam, depending on the entity forming it. For example, if a basestation is forming the uplink beam, it is an uplink receive beam, and ifa UE is forming the uplink beam, it is an uplink transmit beam.

In NR, the frequency spectrum in which wireless nodes (e.g., basestations 802/880, UEs 804/882) operate is divided into multiplefrequency ranges, FR1 (from 450 to 6000 MHz), FR2 (from 24250 to 52600MHz), FR3 (above 52600 MHz), and FR4 (between FR1 and FR2). In amulti-carrier system, such as NR, one of the carrier frequencies isreferred to as the “primary carrier” or “anchor carrier” or “primaryserving cell” or “PCell,” and the remaining carrier frequencies arereferred to as “secondary carriers” or “secondary serving cells” or“SCells.” In carrier aggregation, the anchor carrier is the carrieroperating on the primary frequency (e.g., FR1) utilized by a UE 804/882and the cell in which the UE 804/882 either performs the initial radioresource control (RRC) connection establishment procedure or initiatesthe RRC connection re-establishment procedure. The primary carriercarries all common and UE-specific control channels, and may be acarrier in a licensed frequency (however, this is not always the case).A secondary carrier is a carrier operating on a second frequency (e.g.,FR2) that may be configured once the RRC connection is establishedbetween the UE 804 and the anchor carrier and that may be used toprovide additional radio resources. In some cases, the secondary carriermay be a carrier in an unlicensed frequency. The secondary carrier maycontain only necessary signaling information and signals, for example,those that are UE-specific may not be present in the secondary carrier,since both primary uplink and downlink carriers are typicallyUE-specific. This means that different UEs 804/882 in a cell may havedifferent downlink primary carriers. The same is true for the uplinkprimary carriers. The network is able to change the primary carrier ofany UE 804/882 at any time. This is done, for example, to balance theload on different carriers. Because a “serving cell” (whether a PCell oran SCell) corresponds to a carrier frequency/component carrier overwhich some base station is communicating, the term “cell,” “servingcell,” “component carrier,” “carrier frequency,” and the like can beused interchangeably.

For example, still referring to FIG. 8, one of the frequencies utilizedby the macro cell base stations 802 may be an anchor carrier (or“PCell”) and other frequencies utilized by the macro cell base stations802 and/or the mmW base station 880 may be secondary carriers(“SCells”). The simultaneous transmission and/or reception of multiplecarriers enables the UE 804/882 to significantly increase its datatransmission and/or reception rates. For example, two 20 MHz aggregatedcarriers in a multi-carrier system would theoretically lead to atwo-fold increase in data rate (i.e., 40 MHz), compared to that attainedby a single 20 MHz carrier.

The wireless communications system 800 may further include one or moreUEs, such as UE 890, that connects indirectly to one or morecommunication networks via one or more device-to-device (D2D)peer-to-peer (P2P) links. In the example of FIG. 8, UE 890 has a D2D P2Plink 892 with one of the UEs 804 connected to one of the base stations802 (e.g., through which UE 890 may indirectly obtain cellularconnectivity) and a D2D P2P link 894 with WLAN STA 852 connected to theWLAN AP 850 (through which UE 890 may indirectly obtain WLAN-basedInternet connectivity). In an example, the D2D P2P links 892 and 894 maybe supported with any well-known D2D RAT, such as LTE Direct (LTE-D),WiFi Direct (WiFi-D), Bluetooth®, and so on.

It will be appreciated that the various UEs described herein can includeantenna arrays including multiple antennas, for example, as describedabove with reference to the various modules in FIGS. 5A to 7.

FIG. 9 illustrates an exemplary base station 902 (e.g., an eNB, a gNB, asmall cell AP, a WLAN AP, etc.) in communication with an exemplary UE904 in a wireless network, according to aspects of the disclosure. Thebase station 902 may correspond to any of the base stations describedabove with reference to FIG. 8, and the UE 904 may correspond to any ofthe UEs described above with reference to FIG. 8. The UE 904 may be, ormay include, a DUT, as described herein.

In the DL, IP packets from the core network may be provided to acontroller/processor 975. The controller/processor 975 implementsfunctionality for a radio resource control (RRC) layer, a packet dataconvergence protocol (PDCP) layer, a radio link control (RLC) layer, anda medium access control (MAC) layer. The controller/processor 975provides RRC layer functionality associated with broadcasting of systeminformation (e.g., MIB, SIBs), RRC connection control (e.g., RRCconnection paging, RRC connection establishment, RRC connectionmodification, and RRC connection release), inter-RAT mobility, andmeasurement configuration for UE measurement reporting; PDCP layerfunctionality associated with header compression/decompression, security(ciphering, deciphering, integrity protection, integrity verification),and handover support functions; RLC layer functionality associated withthe transfer of upper layer packet data units (PDUs), error correctionthrough automatic repeat request (ARQ), concatenation, segmentation, andreassembly of RLC service data units (SDUs), re-segmentation of RLC dataPDUs, and reordering of RLC data PDUs; and MAC layer functionalityassociated with mapping between logical channels and transport channels,scheduling information reporting, error correction, priority handling,and logical channel prioritization.

The transmit (TX) processor 916 and the receive (RX) processor 970implement Layer-1 functionality associated with various signalprocessing functions. Layer-1, which includes a physical (PHY) layer,may include error detection on the transport channels, forward errorcorrection (FEC) coding/decoding of the transport channels,interleaving, rate matching, mapping onto physical channels,modulation/demodulation of physical channels, and MIMO antennaprocessing. The TX processor 916 handles mapping to signalconstellations based on various modulation schemes (e.g., binaryphase-shift keying (BPSK), quadrature phase-shift keying (QPSK),M-phase-shift keying (M-PSK), M-quadrature amplitude modulation(M-QAM)). The coded and modulated symbols may then be split intoparallel streams. Each stream may then be mapped to an orthogonalfrequency division multiplexing (OFDM) subcarrier, multiplexed with areference signal (e.g., pilot) in the time and/or frequency domain, andthen combined together using an Inverse Fast Fourier Transform (IFFT) toproduce a physical channel carrying a time domain OFDM symbol stream.The OFDM stream is spatially precoded to produce multiple spatialstreams. Channel estimates from a channel estimator 974 may be used todetermine the coding and modulation scheme, as well as for spatialprocessing. The channel estimate may be derived from a reference signaland/or channel condition feedback transmitted by the UE 904. Eachspatial stream may then be provided to one or more different antennas920 via a separate transmitter 918 a. Each transmitter 918 a maymodulate an RF carrier with a respective spatial stream fortransmission. It will be appreciated that the antennas 920 may be anantenna array including multiple antennas, for example, as describedabove with reference to the various modules in FIGS. 5A to 7.

At the UE 904, each receiver 954 a receives a signal through itsrespective antenna 952 (for example, receiver 954 a-1 receives thesignal through antenna 952-1, etc.). It will be appreciated that theantennas 952 may be an antenna array including multiple antennas(illustrated as antennas 952-1 to 952-n), for example, as describedabove with reference to the various modules in FIGS. 5A to 7. Eachreceiver 954 a recovers information modulated onto an RF carrier andprovides the information to the RX processor 956. The TX processor 968and the RX processor 956 implement Layer-1 functionality associated withvarious signal processing functions. The RX processor 956 may performspatial processing on the information to recover any spatial streamsdestined for the UE 904. If multiple spatial streams are destined forthe UE 904, they may be combined by the RX processor 956 into a singleOFDM symbol stream. The RX processor 956 then converts the OFDM symbolstream from the time-domain to the frequency domain using a fast Fouriertransform (FFT). The frequency domain signal comprises a separate OFDMsymbol stream for each subcarrier of the OFDM signal. The symbols oneach subcarrier, and the reference signal, are recovered and demodulatedby determining the most likely signal constellation points transmittedby the base station 902. These soft decisions may be based on channelestimates computed by the channel estimator 958. The soft decisions arethen decoded and de-interleaved to recover the data and control signalsthat were originally transmitted by the base station 902 on the physicalchannel. The data and control signals are then provided to thecontroller/processor 959, which implements Layer-3 and Layer-2functionality.

The controller/processor 959 can be associated with a memory 960 thatstores program codes and data. The memory 960 may be referred to as acomputer-readable medium. In the UL, the controller/processor 959provides demultiplexing between transport and logical channels, packetreassembly, deciphering, header decompression, and control signalprocessing to recover IP packets from the core network. Thecontroller/processor 959 is also responsible for error detection.

In an aspect, the controller/processor 959 may be configured to set theUE 904 in a simultaneous transmit and receive mode; receive, from a testunit (for example, via “control/data” input to the UE 904 through aconnector, etc., a lower frequency RF signal; up-convert, via anup-converter, the lower frequency RF signal to a higher frequency RFsignal; transmit, via a first antenna 952, the higher frequency RFsignal; receive, via a second antenna 952, the higher frequency RFsignal; down-convert, via a down-converter, the received higherfrequency RF signal to a received test RF signal; and provide, via oneor more transmitters 954 b and antennas 952, the received test RF signalto the test unit. Alternatively, any combination of controller/processor959, RX processor 956, and TX processor 968 may be configured to performthese operations. In an aspect, the up-converter may be implemented inthe transmit processor 968, the respective transmitter 954 b, or anycombination thereof, and the down-converter may be implemented in thereceive processor 956, the respective receiver 954, or any combinationthereof.

Similar to the functionality described in connection with the DLtransmission by the base station 902, the controller/processor 959provides RRC layer functionality associated with system information(e.g., MIB, SIBs) acquisition, RRC connections, and measurementreporting; PDCP layer functionality associated with headercompression/decompression, and security (ciphering, deciphering,integrity protection, integrity verification); RLC layer functionalityassociated with the transfer of upper layer PDUs, error correctionthrough ARQ, concatenation, segmentation, and reassembly of RLC SDUs,re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; andMAC layer functionality associated with mapping between logical channelsand transport channels, multiplexing of MAC SDUs onto TBs,demultiplexing of MAC SDUs from TBs, scheduling information reporting,error correction through HARQ, priority handling, and logical channelprioritization.

Channel estimates derived by the channel estimator 958 from a referencesignal or feedback transmitted by the base station 902 may be used bythe TX processor 968 to select the appropriate coding and modulationschemes, and to facilitate spatial processing. The spatial streamsgenerated by the TX processor 968 may be provided to different antenna952 via separate transmitters 954 b. Each transmitter 954 b may modulatean RF carrier with a respective spatial stream for transmission. In anaspect, the transmitters 954 b and the receivers 954 a may be one ormore transceivers, one or more discrete transmitters, one or morediscrete receivers, or any combination thereof.

In an aspect, each transmitter 954 b (illustrated as transmitters 954b-1 to 954 b-n) may comprise a separate transmit chain (e.g., phaseshifter, mixer, power amplifier, antenna 952, etc.), and each receiver954 a (illustrated as transmitter 954 a-1 to 954 a-n) may comprise aseparate receive chain (e.g., phase shifter, mixer, low noise amplifier(LNA), antenna 952, etc.). As such, it is understood that for a givenantenna combination, it is possible for the transmit path of a transmitantenna to be electrically independent of a receive path of a receiveantenna. Isolating the transmit path (including transmitter 954 b) of afirst antenna from the receive path (including receiver 954) of a secondantenna can enable simultaneous or near simultaneous transmission andreception of test signals as described herein. In an aspect, groups ofone or more receivers 954 a/transmitters 954 b and correspondingantennas 952 may correspond to a different layer. The term “layer” issynonymous with “stream.” For MIMO operation, at least two layers mustbe used. In some cases, up to four layers may be allowed. The number oflayers is always less than or equal to the number of antennas 952. TheUE 904, when being tested as described herein, needs to be able tooperate on at least two layers to simultaneously transmit and receive,as described herein.

The UL transmission from the UE 904 is processed at the base station 902in a manner similar to that described in connection with the receiverfunction at the UE 904. Each receiver 918 b receives a signal throughits respective antenna 920. Each receiver 918 b recovers informationmodulated onto an RF carrier and provides the information to a RXprocessor 970. In an aspect, the transmitters 918 a and the receivers918 b may be one or more transceivers, one or more discretetransmitters, one or more discrete receivers, or any combinationthereof.

The controller/processor 975 can be associated with a memory 976 thatstores program codes and data. The memory 976 may be referred to as acomputer-readable medium. In the UL, the controller/processor 975provides demultiplexing between transport and logical channels, packetreassembly, deciphering, header decompression, control signal processingto recover IP packets from the UE 904. IP packets from thecontroller/processor 975 may be provided to the core network. Thecontroller/processor 975 is also responsible for error detection.

Those skilled in the art will appreciate that information and signalsmay be represented using any of a variety of different technologies andtechniques. For example, data, instructions, commands, information,signals, bits, symbols, and chips that may be referenced throughout theabove description may be represented by voltages, currents,electromagnetic waves, magnetic fields or particles, optical fields orparticles, or any combination thereof.

Further, those skilled in the art will appreciate that the variousillustrative logical blocks, modules, circuits, and algorithm stepsdescribed in connection with the aspects disclosed herein may beimplemented as electronic hardware, computer software, or combinationsof both. To clearly illustrate this interchangeability of hardware andsoftware, various illustrative components, blocks, modules, circuits,and steps have been described above generally in terms of theirfunctionality. Whether such functionality is implemented as hardware orsoftware depends upon the particular application and design constraintsimposed on the overall system. Skilled artisans may implement thedescribed functionality in varying ways for each particular application,but such implementation decisions should not be interpreted to departfrom the scope of the various aspects described herein.

The various illustrative logical blocks, modules, and circuits describedin connection with the aspects disclosed herein may be implemented orperformed with a general purpose processor, a digital signal processor(DSP), an application specific integrated circuit (ASIC), a fieldprogrammable gate array (FPGA) or other programmable logic device,discrete gate or transistor logic, discrete hardware components, or anycombination thereof designed to perform the functions described herein.A general purpose processor may be a microprocessor, but in thealternative, the processor may be any conventional processor,controller, microcontroller, or state machine. A processor may also beimplemented as a combination of computing devices (e.g., a combinationof a DSP and a microprocessor, a plurality of microprocessors, one ormore microprocessors in conjunction with a DSP core, or other suchconfigurations).

The methods, sequences, and/or algorithms described in connection withthe aspects disclosed herein may be embodied directly in hardware, in asoftware module executed by a processor, or in a combination of the two.A software module may reside in random access memory (RAM), flashmemory, read-only memory (ROM), erasable programmable ROM (EPROM),electrically erasable programmable ROM (EEPROM), registers, hard disk, aremovable disk, a CD-ROM, or any other form of non-transitorycomputer-readable medium known in the art. An exemplary non-transitorycomputer-readable medium may be coupled to the processor such that theprocessor can read information from, and write information to, thenon-transitory computer-readable medium. In the alternative, thenon-transitory computer-readable medium may be integral to theprocessor. The processor and the non-transitory computer-readable mediummay reside in an ASIC. The ASIC may reside in a user device (e.g., a UE)or a base station. In the alternative, the processor and thenon-transitory computer-readable medium may be discrete components in auser device or base station.

In one or more exemplary aspects, the functions described herein may beimplemented in hardware, software, firmware, or any combination thereof.If implemented in software, the functions may be stored on ortransmitted over as one or more instructions or code on a non-transitorycomputer-readable medium. Computer-readable media may include storagemedia and/or communication media including any non-transitory mediumthat may facilitate transferring a computer program from one place toanother. A storage media may be any available media that can be accessedby a computer. By way of example, and not limitation, suchcomputer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or otheroptical disk storage, magnetic disk storage or other magnetic storagedevices, or any other medium that can be used to carry or store desiredprogram code in the form of instructions or data structures and that canbe accessed by a computer. Also, any connection is properly termed acomputer-readable medium. For example, if the software is transmittedfrom a website, server, or other remote source using a coaxial cable,fiber optic cable, twisted pair, digital subscriber line (DSL), orwireless technologies such as infrared, radio, and microwave, then thecoaxial cable, fiber optic cable, twisted pair, DSL, or wirelesstechnologies such as infrared, radio, and microwave are included in thedefinition of a medium. The term disk and disc, which may be usedinterchangeably herein, includes compact disk (CD), laser disc, opticaldisc, digital video disk (DVD), floppy disk, and Blu-ray discs, whichusually reproduce data magnetically and/or optically with lasers.Combinations of the above should also be included within the scope ofcomputer-readable media.

For example, one aspects of the disclosure can include a non-transitorycomputer-readable medium including code, which, when executed by aprocessor, causes the processor to perform operations for self-radiatedloopback testing of a DUT.

While the foregoing disclosure shows illustrative aspects, those skilledin the art will appreciate that various changes and modifications couldbe made herein without departing from the scope of the disclosure asdefined by the appended claims. Furthermore, in accordance with thevarious illustrative aspects described herein, those skilled in the artwill appreciate that the functions, steps, and/or actions in any methodsdescribed above and/or recited in any method claims appended hereto neednot be performed in any particular order. Further still, to the extentthat any elements are described above or recited in the appended claimsin a singular form, those skilled in the art will appreciate thatsingular form(s) contemplate the plural as well unless limitation to thesingular form(s) is explicitly stated.

What is claimed is:
 1. A method of testing a device under test (DUT)performed by the DUT, the method comprising: setting the DUT in asimultaneous transmit and receive mode; receiving a lower frequencyradio frequency (RF) signal from a test unit; up-converting the lowerfrequency RF signal to a higher frequency RF signal; transmitting thehigher frequency RF signal using a first antenna of the DUT; receivingthe higher frequency RF signal using a second antenna of the DUT;down-converting the received higher frequency RF signal to a receivedtest RF signal; and providing the received test RF signal to the testunit.
 2. The method of claim 1, wherein the DUT transmits on a firstmultiple-input and multiple-output (MIMO) layer and receives on a secondMIMO layer.
 3. The method of claim 1, wherein the first antenna and thesecond antenna are selected from a plurality of antennas of the DUT. 4.The method of claim 3, wherein the plurality of antennas are coupled tothe DUT prior to testing.
 5. The method of claim 3, wherein the firstantenna and the second antenna are separated by at least one otherantenna of the plurality of antennas.
 6. The method of claim 3, whereinthe plurality of antennas includes one or more dipole antennas and oneor more patch antennas.
 7. The method of claim 6, wherein the firstantenna and the second antenna are both dipole antennas.
 8. The methodof claim 6, wherein the first antenna and the second antenna are bothpatch antennas.
 9. The method of claim 1, wherein the transmitting andreceiving are performed by a single transceiver integrated circuit (IC)that is part of the DUT.
 10. The method of claim 1, further comprising:receiving a second lower frequency RF signal from the test unit;up-converting the second lower frequency RF signal to a second higherfrequency RF signal; transmitting the second higher frequency RF signalusing the second antenna; receiving the second higher frequency RFsignal using the first antenna; down-converting the received secondhigher frequency RF signal to a second received test RF signal; andproviding the second received test RF signal to the test unit.
 11. Themethod of claim 10, wherein the lower frequency RF signal and the secondlower frequency RF signal are the same.
 12. The method of claim 1,wherein the lower frequency RF signal received from the test unitcomprises a multi-tone RF signal.
 13. The method of claim 1, wherein thelower frequency RF signal comprises a non-millimeter wave RF signal andthe higher frequency RF signal comprises a millimeter wave RF signal.14. A method of testing a device under test (DUT) performed by a testunit, the method comprising: configuring the DUT to set a simultaneoustransmit and receive mode; generating a lower frequency radio frequency(RF) signal, the test unit comprising only lower frequency RFcomponents; providing the lower frequency RF signal to the DUT;receiving a received test RF signal from the DUT; and comparingmeasurements derived from the received test RF signal to a designspecification for the DUT.
 15. The method of claim 14, wherein comparingmeasurements further comprises: calculating and comparing receiver gainand transmit power at the DUT to the design specification.
 16. Themethod of claim 14, wherein the test unit generates the lower frequencyRF signal from a signal generator.
 17. The method of claim 14, whereinthe lower frequency RF signal comprises a multi-tone RF signal.
 18. Themethod of claim 14, wherein the lower frequency RF signal comprises anon-millimeter wave RF signal.
 19. A device under test (DUT),comprising: a memory; a plurality of antennas coupled to the at leastone processor, the plurality of antenna comprising at least a firstantenna and a second antenna, wherein a transmit path for the firstantenna is electrically independent of a receive path of the secondantenna; an up-converter and a down-converter; and at least oneprocessor coupled to the memory, the at least one processor configuredto: set the DUT in a simultaneous transmit and receive mode; receive alower frequency radio frequency (RF) signal from a test unit;up-convert, via the up-converter, the lower frequency RF signal to ahigher frequency RF signal; transmit, via the first antenna, the higherfrequency RF signal; receive, via the second antenna, the higherfrequency RF signal; down-convert, via the down-converter, the receivedhigher frequency RF signal to a received test RF signal; and provide thereceived test RF signal to the test unit.
 20. The DUT of claim 19,wherein the first antenna and the second antenna are separated by atleast one other antenna of the plurality of antennas.
 21. The DUT ofclaim 19, wherein the plurality of antennas includes one or more dipoleantennas and one or more patch antennas.
 22. The DUT of claim 21,wherein the first antenna and the second antenna are both dipoleantennas, or wherein the first antenna and the second antenna are bothpatch antennas.
 23. The DUT of claim 19, wherein the lower frequency RFsignal comprises a non-millimeter wave RF signal and the higherfrequency RF signal comprises a millimeter wave RF signal.
 24. Themethod of claim 19, wherein the first antenna and the second antenna areseparated by at least one other antenna of the plurality of antennas.25. The method of claim 19, wherein the plurality of antennas includesone or more dipole antennas and one or more patch antennas.
 26. Themethod of claim 25, wherein the first antenna and the second antenna areboth dipole antennas, or wherein the first antenna and the secondantenna are both patch antennas.
 27. A device test system, including atest unit, wherein the test unit comprises: a signal generatorconfigured to generate a lower frequency RF signal and to provide thelower frequency radio frequency (RF) signal to a device under test(DUT), the test unit comprising only lower frequency RF components; asignal analyzer configured to receive a received test RF signal from theDUT and to compare measurements from the received test RF signal to adesign specification for the DUT; and a fixture for mounting the DUT tothe test unit.
 28. The device test system of claim 27, wherein thesignal analyzer is further configured to calculate and compare receivergain and transmit power of the DUT to the design specification for theDUT.
 29. The device test system of claim 27, wherein the signal analyzeris a vector signal analyzer (VSA).
 30. The device test system of claim27, wherein the lower frequency RF signal comprises a non-millimeterwave RF signal and the higher frequency RF signal comprises a millimeterwave RF signal.